1. Field of the Invention
The invention pertains to an appliance for correcting tooth and/or jaw malpositions, with an upper and a lower arch wire, which are attached to the teeth and which are connected mechanically to each other by at least one force-transfer element, usually by two force-transfer elements.
2. Description of the Related Art
The advantages of tooth-mounted appliances for correcting malpositions of the teeth and/or jaws have been recognized by orthodontists and dentists for many years. The mechanical connection of the upper jaw to the lower jaw to improve the occlusion, however, still represents a problem. There are only four possible ways to connect the upper and lower jaws together.
First, a distinction must be made between a rigid and a flexible connection. In addition, the jaws can be either moved toward each other, i.e., by exerting pulling forces on them, or they can be moved away from each other, i.e., by exerting pushing forces on them. These possibilities lead to the various appliances for mechanically connecting the jaws. Although no rigid pulling applications are known, elastic pulling applications can be designed with the help of elastic bands or springs. An example of a rigid pushing application is Herbst's hinge. A flexible pushing application is known in the form of the so-called “Jasper jumper”, described in U.S. Pat. No. 4,708,646.
The known appliances are of complicated design and usually have bulky, bent compression springs, of which a very wide variety must be kept on hand to fulfill all the necessary functions. In particular, a progressive jaw correction requires the use of a series of new components to fit the changing size of the jaws.